When Paul Le Roux was last inside a St. Paul federal courtroom, he casually discussed being the architect behind seven murders, dealing weapons and drugs around the globe, and doing business in some of the world’s most dangerous places.

An alleged “global criminal mastermind” who has been held at an undisclosed location in New York since his 2012 arrest in Liberia, Le Roux will soon return to Minnesota to testify in the trial of two men who claim they worked for him under fear of death.

Moran Oz, an Israeli national, and Lachlan Scott McConnell, a Canadian citizen, are among four men whose trial began this week on charges that they helped Le Roux operate an international illegal online pharmacy called RX Limited. The trial is expected to span at least six weeks as attorneys present volumes of electronic records gathered during an investigation started by DEA investigators in Minnesota 10 years ago.

The trial’s most compelling testimony is likely to emerge when the defendants’ lawyers call Le Roux and another associate now serving a federal prison sentence for attempting to murder an undercover agent. An alleged kingpin turned government informant, Le Roux has helped federal prosecutors put together several cases, including the one unfolding in St. Paul.

Before jury selection began Monday, U.S. District Judge Susan Richard Nelson ruled that Oz and McConnell can pursue what are called “duress defenses” and call their former boss to testify in front of jurors.

Oz, who allegedly managed RX Limited’s call centers in Israel and oversaw the delivery of prescription drugs, is expected to argue that he thought the company he joined was legitimate before learning the true nature of his boss’ dealings in a near fatal 2009 encounter.

According to his attorneys, Oz was tossed into open ocean water during a visit near the Philippines in 2009. One of Le Roux’s associates on the boat fired into the water around Oz while another accused him of betraying Le Roux. Oz said he was given a choice: confess and be killed or deny and be wounded and left for sharks. The men eventually told Le Roux by phone that Oz appeared truthful, and he was hauled back onto the boat, tranquilized and held another day.

McConnell, who worked private security for Le Roux in places like the Congo and Zimbabwe, said his duties expanded from overseeing construction of a Filipino gun club to helping ship gold bars around the world. After the man who introduced McConnell to Le Roux was killed, when Le Roux suspected the two of stealing his gold, McConnell said he was ordered to help work with RX Limited in the United States to repay his betrayal.

In her ruling last week, Nelson concluded that the two had “described in vivid detail the specific threats Le Roux leveled at them.” Le Roux, Nelson wrote, had demonstrated an ability to locate and monitor the men through “his network of corrupted government officials and henchmen.”

The four on trial — Oz, McConnell and former RX Limited physicians Elias Karkalas and Prabhakara Tumpati — were among 11 people indicted in 2013 on conspiracy charges, mail fraud, wire fraud and money laundering.

Prosecutors outline an eight-year scheme that began in 2004 and generated sales of more than $200 million in prescription drugs without physical examinations or valid doctor-patient relationships.

“Dozens of physicians (including would-be physicians without medical degrees) authorized hundreds of drug orders each day in return for commissions from RXL, based solely on limited and unverified information provided by customers. ...” Roger Gural, a trial attorney for the Consumer Protection Branch of the Justice Department, wrote in a brief filed before trial.

On Wednesday, prosecutors called their first witness, a former Minneapolis DEA investigator who testified that undercover purchases by fellow investigator Kimberly Brill in 2007 touched off the case that later helped bring down Le Roux. Brill will be seated throughout trial with the prosecution, who called her participation essential.

Wednesday’s proceedings concluded with Robert Richman, one of Oz’s two attorneys, cross-examining the former DEA investigator, Steven Holdren, and raising questions about Le Roux.

Le Roux still awaits sentencing under a previously sealed plea agreement in New York that included his involvement in the RX Limited scheme and other charges that include “exporting prohibited technology to Iran” and computer hacking.

Before trial, the government argued against any claims of duress by defendants who worked under Le Roux, saying Oz and McConnell had “recklessly or negligently” worked for their boss despite knowledge of his criminal behavior. But Nelson said last week that such arguments missed the point: Oz and McConnell didn’t start out working for a well-known villain like Joaquin “El Chapo” Guzman or James “Whitey” Bulger, she said.

“It was only after defendants were entangled in Le Roux’s ‘web’ that they became aware of the criminal nature of the enterprise and Le Roux’s violent tendencies,” Nelson wrote. “By then they argue, it was too late and they could not escape without incurring Le Roux’s wrath.”

“It is for the jury to decide what evidence is credible.”